FUSB302TMPX datasheet(11/36 Pages) ONSEMI

11 / 36 page

Flush Rx-FIFO with Built-In Self Test

(BIST) Test Data.

During PD compliance testing, BIST test packets are

used to test physical layer of the PD interface such as,

frequency derivation, Amplitude measure and etc. The

one BIST test data packet has 7 data objects (28byte

data), header and CRC, but the message ID doesn

‟t

change, the packet should be ignored and not acted on

by the PD policy engine. The PD protocol layer does

need to send a GoodCRC message back after every

packet. The BIST data can arrive continuously from a

tester, which could cause the FUSB302T Rx FIFO to

overflow and the PD protocol layer to stop sending

GoodCRC messages unless the FIFO is read or cleared

quickly. The FUSB302T has a special register bit in the

I2C registers, bit[5] of address 0x09, that when the bit is

set, all the data received next will be flushed from the

RxFIFO automatically and the PD protocol layer will

keep sending GoodCRC messages back. Once BIST

test is done, tester sends HardReset, so with the

HardReset, processor has to write the bit back to

disable. Also, if the bit can be de-selected anytime, then

the coming packet has to be managed by protocol layer

and policy engine.

FUSB302TMPX Datasheet(PDF) 11 Page - ON Semiconductor